JP2000320465A - Control valve for variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure with superior reliability in opening and closing operation of a valve element, to prevent the increase of the number of item parts and the number of assembling processes, and basides to prevent complication of passage structure, in a control valve to perform control of capacity related to outside air load. SOLUTION: A control valve for a variable displacement compressor comprises a ball valve element 38 for opening and closing an communication passage 34 to effect communication between the suction port and the crank chamber of a compressor, a spring to energize the ball valve element 38 in a closing direction, and a diaphragm device 43 to drive the ball valve element 38 in a closing direction by exerting the suction pressure of the compressor on a diaphragm chamber 49. The spring is formed of an ordinary spring material and constituted through combination of a main spring 54 to energize the ball valve element 38 in the closing direction and a correction spring 55 formed of a temperature-sensitive material, having positive characteristics to an outside air temperature and exerting a force in the direction in which the spring force of the main spring 54 is offset thereby. A spring force in a closing direction is decreased accompanying the increase in the outside air temperature representative of the outside air load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve for a variable displacement compressor, and more particularly, to a displacement control valve for a swash plate type variable displacement compressor used in a vehicle air conditioner or the like.

[0002]

2. Description of the Related Art As a capacity control valve for a swash plate type variable displacement compressor, Japanese Patent Publication No. 3-53474 and Japanese Utility Model Publication No.
A capacity control valve disclosed in JP-A-17010 and JP-A-8-177735 is conventionally known.

[0003] This displacement control valve basically reduces the displacement in response to a rise in the pressure in the crankcase of a compressor incorporating a swash plate, and increases the displacement in response to a decrease in the pressure in the crankcase. In a variable displacement type compressor, a communication passage communicating a suction port of the compressor with a crank chamber is opened and closed by a valve element responsive to the suction pressure of the compressor, and the suction pressure of the compressor is supplied to the crank chamber. A control valve that controls the discharge pressure of the compressor in the valve opening direction, shifts the opening / closing operation point of the valve element according to the discharge pressure, and correlates with the outside air load (discharge pressure). It is configured to perform control.

[0004]

The above-mentioned conventional capacity control valves all achieve the intended purpose uniformly, however, in order to perform capacity control correlated with the external air load (cooling load). A structure for giving the discharge pressure of the compressor in the valve opening direction, for example, incorporating an actuation rod, an operating rod, providing a high pressure correction pressure chamber, and providing a passage for giving the compressor discharge pressure to them. Must be provided.

[0005] For this reason, the opening and closing operation of the valve element is lacking in reliability, the number of parts and the number of assembling steps are increased, and when the valve is directly incorporated in the compressor housing, the suction pressure and discharge pressure are applied to each part of the displacement control valve. The structure of the passage for conducting the pressure becomes complicated, and the degree of freedom of the arrangement position in the compressor housing is limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a simple structure as a control valve capable of performing a capacity control in relation to an external air load. , Variable capacity without increasing the number of parts and assembling man-hours, and as a compressor housing built-in type, without complicating the passage structure, and with excellent flexibility in arrangement position in the compressor housing It is an object of the present invention to provide a control valve for a type compressor.

[0007]

In order to achieve the above object, a control valve for a variable displacement compressor according to the first aspect of the present invention provides a communication passage for communicating a suction port of the compressor with a crank chamber. A valve housing that opens and closes the communication passage, a spring that urges the valve body in the valve closing direction, and drives the valve body in the valve opening direction by receiving the suction pressure of the compressor. In the control valve for a variable displacement compressor having a pressure responsive device, the spring includes a spring made of a temperature-sensitive material and responsive to an outside air temperature, and reduces a spring force in a valve closing direction with an increase in the outside air temperature. Is what you do.

According to a second aspect of the present invention, there is provided a control valve for a variable displacement compressor, wherein the spring is made of a normal spring material, and a main spring for urging the valve body in a valve closing direction is provided. On the other hand, it is composed of a temperature-sensitive material having a positive characteristic, and is configured by a combination with a correction spring in which a spring force acts in a direction to cancel the spring force of the main spring with a force smaller than the spring force of the main spring, The combined spring force of the spring force of the main spring and the spring force of the correction spring acts on the valve body.

According to a third aspect of the present invention, in the control valve for a variable displacement compressor, the correction spring is made of a shape memory alloy.

According to a fourth aspect of the present invention, in the control valve for a variable displacement compressor, the valve housing is inserted and fixed in a control valve receiving hole formed in a housing of the compressor.
The pressure responsive device is fixed to one end of the valve housing, and the pressure responsive device is configured to be attached to a housing of the compressor so as to be exposed to the outside from the control valve receiving hole. A spring is incorporated.

In the control valve for a variable displacement compressor according to the first aspect of the present invention, the spring force in the valve closing direction of the spring for urging the valve body in the valve closing direction decreases as the outside air temperature increases. Therefore, the displacement control is performed in correlation with the outside air load represented by the outside air temperature which is proportional to the compressor discharge pressure.

In the control valve for a variable displacement compressor according to the second aspect of the present invention, the spring force in the valve closing direction of the main spring and the spring force of the correction spring acting in the direction of canceling the spring force of the main spring. (The spring force of the main spring> the spring force of the correction spring) acts on the valve body, and the correction spring is made of a temperature-sensitive material having a positive characteristic with respect to temperature.

In the control valve for a variable displacement compressor according to the third aspect of the present invention, the correction spring is made of a shape memory alloy (SMA) having a positive characteristic with respect to temperature.

In the control valve for a variable displacement compressor according to the present invention, the spring incorporated in the pressure responsive device is sensitive to the outside air temperature.

[0015]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a variable displacement compressor incorporating a control valve according to the present invention, and FIG. 2 shows a displacement control valve according to the present invention.

The swash plate type variable displacement compressor 1 includes a crank chamber 3 defined by a compressor housing 2 and a plurality of cylinder chambers 4 each communicating with the crank chamber 3 at one stroke end. Have. A piston 5 is fitted in each of the cylinder chambers 4 so as to be slidable in the axial direction. One end of a piston rod 6 is connected to the side of the crank chamber 3 of each piston 5.

The compressor housing 2 rotatably supports a drive shaft 7. The drive shaft 7 is drivingly connected to an engine (not shown) by a drive belt (not shown) stretched over a pulley 8. Is driven to rotate.

The drive shaft 7 is connected to a wobble plate (swash plate) 9 in the crank chamber 3 by a known connecting mechanism (not shown) in a torque transmitting relationship so that the mounting angle can be changed.
The piston rod 6 is engaged with the plate surface of the wobble plate 9 on the cylinder chamber 4 side so as to be able to transmit an axial force.

When the wobble plate 9 is rotated by the drive shaft 7 in an inclined state, the piston 5 of each cylinder chamber 4 reciprocates with a stroke corresponding to the inclination angle of the wobble plate 9, and the inclination angle is determined by the crank angle. The pressure is automatically adjusted in accordance with the pressure difference between the chamber pressure Pc and the suction pressure (compressor suction pressure) Ps of each cylinder chamber 4.

In this case, the compressor 1 has a crank chamber pressure P
c, the inclination angle of the wobble plate 9 is reduced and the stroke of the piston 5 is reduced to reduce the displacement, and the wobble plate 9 is reduced in response to the decrease in the crank chamber pressure Pc.
As the stroke of the piston 5 increases and the stroke of the piston 5 increases, the displacement increases, and the crank chamber pressure Pc becomes substantially equal to the suction pressure Ps, whereby the engine enters a full load operation state.

Each cylinder chamber 4 has a suction port 14 and a discharge port 15 each having a one-way valve having a suction valve 12 and a discharge valve 13. The suction port 14 of each cylinder chamber 4 is formed by a suction passage 16. The suction port 17 communicates with the suction port 17, and the discharge port 15 communicates with the discharge connection port 19 through the discharge passage 18. The evaporator 20, the expansion valve 21, the condenser 22, and the like are connected to the suction connection port 17 and the discharge connection port 19. Is connected.

A control valve receiving hole 23 having a bottomed hole is formed in the compressor housing 2.
The control valve 30 according to the present invention is inserted and fixed therein.

The control valve 30 has a cylindrical valve housing 31 inserted into the control valve receiving hole 23.

The valve housing 31 includes a valve housing 31.
Extends in the axial direction (vertical direction), and extends radially across the intermediate portion between the crank chamber side passage 32 and the valve housing 31 that is opened at one end surface (upper end surface) of the valve housing 31. A T-shaped communication passage 34 formed by the suction port side passage 33 and one end communicates with an intersection of the crank chamber side passage 32 and the suction port side passage 33, and extends axially through the center of the valve housing 31. The valve rod engaging hole 3 serving also as a valve chamber 35 opened on the other end surface (lower end surface) of the valve housing 31.
6 are formed.

A filter 37 is mounted on the upper end surface of the valve housing 31 so as to cover the open end of the passage 32 on the crank chamber side.

A ball valve 38 is disposed in the valve chamber 35. The ball valve element 38 opens and closes the communication passage 34 by selectively seating on the valve seat portion 39 in the valve housing 31.

A valve rod 40 is fitted in the valve rod engaging hole 36 so as to be slidable in the axial direction. The valve stem 40 is connected to the ball valve body 38 at one end (upper end).

The other end (lower end) of the valve housing 31 is on the open end side of the control valve receiving hole 23 of the compressor housing 2, and this other end is exposed to the outside through the control valve receiving hole 23. A diaphragm device 43 as a pressure responsive device is fixedly mounted.

The diaphragm device 43 includes the valve housing 3
1, a dish-shaped upper lid 44 which is swaged to the other end, a dish-shaped lower lid 46 which is joined to the upper lid 44 with a diaphragm 45 interposed therebetween, and a cylindrical spring box 4 which is swaged to the lower lid 46.
7 and an adjusting screw 48 threadedly engaged with the spring box 47.

The diaphragm 45 is connected to the valve stem 40, and defines a diaphragm chamber 49 on the valve housing 31 side and a closed chamber 50 on the spring box 47 side with the diaphragm 45 interposed therebetween. The other end (lower end) of the valve stem 40 is connected. In addition, the diaphragm chamber 4
Numeral 9 communicates with the valve chamber 35 through a gap (not shown) existing in the valve rod engaging hole 36 and the valve rod 40, and the suction pressure Ps of the compressor 1 is introduced from the valve chamber 35 as a pressure in the valve opening direction. Is done.

On the side of the closed chamber 50 of the diaphragm 45, there are provided an abutment 51, a ball 52, and a spring receiving member 53 in order. Between the spring receiving member 53 and the adjusting screw 48, the diaphragm 45, the valve stem 40 There is provided a main spring 54 for urging the ball valve body 38 in the valve closing direction (upward) via the. The main spring 54 is formed of a compression coil spring made of a normal spring material having substantially no temperature dependency, such as spring steel.

The spring box 47 and the spring receiving member 53 are formed with spring receiving flanges 47a and 53a for correction springs, respectively. The spring force of the main spring 54 is canceled between the spring receiving flanges 47a and 53a. A correction spring 55 is provided which acts in the direction of movement.

The correction spring 55 is made of a temperature-sensitive material having a positive characteristic with respect to temperature, for example, a shape memory alloy (SMA), and is located in the spring box 47 of the diaphragm device 43 and responds to the outside air temperature T. FIG. 4 shows an outside air temperature-corrected spring load characteristic as shown in FIG. 3. Note that the maximum spring force of the correction spring 55 is set to a value smaller than the spring force of the main spring 54, and the relationship of the spring force of the main spring 54> the spring force of the correction spring 55 is always maintained.

The correction spring 55 increases the correction spring load W with an increase in the outside air temperature T. As a result, the combined spring force (valve closing force) of the spring force of the main spring 54 and the correction spring 55 is reduced by the outside air. It decreases as the temperature T rises.

Further, between the valve stem 40 and the valve housing 31, there is provided a middle spring 56 made of a compression coil spring which is extremely weaker than the minimum value of the above-mentioned combined spring force.

The control valve 30 having the above-described configuration is inserted and fixed in the control valve receiving hole 23 of the compressor housing 2, and the crank chamber side passage 32 is connected to the crank chamber pressure passage 24 opening at the bottom of the control valve receiving hole 23. The suction port side passage 33 communicates with the suction port 14 through the suction pressure passage 25. The crank chamber pressure passage 24 and the suction pressure passage 25 are connected to the compressor housing 2.
Is a pressure passage formed inside.

Next, the operation of the capacity control valve 30 having the above configuration will be described.

When the suction pressure Ps of the compressor 1 is
4 through a suction pressure passage 25, a suction port side passage 33, and a valve chamber 35 to enter a diaphragm chamber 49.
Is driven in the valve opening direction.

Assuming that the valve closing force of the ball valve body 38 is constant,
The ball valve body 38 is driven to open and close by an equilibrium relationship between the valve opening force due to the suction pressure Ps acting on the diaphragm 45 and the valve closing force due to the spring force of the main spring 54 minus the spring force of the correction spring 55. Here, the spring force of the middle spring 56 is ignored since the spring force of the middle spring 56 is weak and constant, and thus has little effect on the control valve characteristics.

Accordingly, when the suction pressure Ps becomes equal to or less than the control valve set pressure (reference set pressure Pss) determined by the combined spring force of the main spring 54 and the correction spring 55, the spring force of the main spring 54 and The diaphragm 45 is displaced upward in FIGS. 1 and 2 by the combined spring force with the spring force of the correction spring 55, and the ball valve body 38 is closed and moved via the valve rod 40 and seated on the valve seat portion 39. And close the valve.

Thus, the supply of the suction pressure Ps to the crank chamber 3 is stopped, the crank chamber pressure Pc increases, and the compressor 1 enters the unload operation state.

On the other hand, when the suction pressure Ps becomes equal to or higher than the control valve set pressure (reference set pressure Pss), the diaphragm 45 resists the combined spring force of the main spring 54 and the correction spring 55. 1 and 2, the ball valve element 38 is opened via the valve rod 40, and the valve seat 39 is opened.
And open.

As a result, the suction pressure Ps is supplied to the crank chamber 3, the crank chamber pressure Pc becomes equal to the suction pressure Ps, and the compressor 1 enters a full load operation state.

As described above, when the combined spring force acting as the valve closing force is constant, that is, when the high pressure correction is not performed, the compressor 1 is indicated by a broken line in FIG. Thus, the capacity control operation in which the suction pressure Ps is constant at the reference set pressure Pss is performed.

The combined spring force of the spring force of the main spring 54 and the spring force of the correction spring 55 is such that the correction spring 55 increases the correction spring load W with the rise of the outside air temperature T.
It decreases with the rise of Thus, the suction pressure Ps required for opening the valve increases due to the decrease in the outside air temperature T, and the suction pressure Ps required for opening the valve decreases due to the increase in the outside air temperature T.

The outside air temperature T at the reference discharge pressure Pds is Ts, and the correction spring load W at the outside air temperature Ts is Ws
And the effective pressure receiving area Ad of the diaphragm 45,
When the outside air temperature T falls below the outside air temperature Ts, the valve closing force increases by (Ws−W) from the reference time, and the valve opening pressure becomes (Ws−W).
W) / Ad, and conversely, when the outside air temperature T rises above the outside air temperature Ts, the valve closing force becomes (WW).
s), the valve opening pressure drops by (W-Ws) / A
A pressure characteristic that decreases according to d is obtained.

This is shown by the following equation. Ps = Pss- (W-Ws) / Ad

As a result, as shown by the solid line in FIG. 4, a control characteristic in which the suction pressure Ps decreases in proportion to the rise in the outside air temperature T is obtained, and the outside air temperature T (discharge) correlated with the system load characteristic. The control characteristics of the displacement control compressor can be matched by the pressure Pd).

This means that in the refrigerant circuit system, the evaporation load and the condensation load are in a proportional relationship, the evaporation load is proportional to the refrigerant circulation amount, and the pressure loss in the evaporator is proportional to the refrigerant circulation amount. As a result, the capacity control of the compressor can be realized as an efficient energy saving system.

In the above embodiment, the pressure responsive device is the diaphragm device 43, but the pressure responsive device is
The present invention is not limited to the diaphragm device 43, but may be a bellows having a closed structure.

A control valve for a variable displacement compressor in which the pressure responsive device is constituted by a bellows having a closed structure will be described with reference to FIG. In FIG. 5, the parts corresponding to FIG.
The same reference numerals are given to the reference numerals, and the description is omitted.

In this embodiment, a bellows 58 integrally having an end plate 57 is attached to the valve housing 31.
Bellows 58 defines a sealed chamber 50 on the inside. The bellows 58 is connected to a holding body 59 of the ball valve body 38 at an end plate 57.

The chamber 60 outside the bellows 58 communicates with the valve chamber 35, and the bellows 58 receives the suction pressure Ps introduced from the valve chamber 35 into the bellows storage case 68 in the valve opening direction, and the suction pressure increases. It expands and contracts according to the pressure difference between Ps and the bellows internal pressure.

Also in this embodiment, since the correction spring 55 is made of a temperature-sensitive material having a positive characteristic with respect to temperature, the same operation and effect as those of the above-described embodiment can be obtained.

[0056]

As can be understood from the above description, the control valve for a variable displacement compressor according to the first aspect of the present invention has a communication passage communicating the suction port of the compressor with the crank chamber. A valve housing, a valve body for opening and closing the communication passage, a spring for urging the valve body in a valve closing direction, and a pressure responsive to receiving the suction pressure of the compressor to drive the valve body in a valve opening direction. A control valve for a variable displacement compressor having a device, wherein the spring includes a spring made of a temperature-sensitive material and responsive to an outside air temperature, and reduces a spring force in a valve closing direction with an increase in the outside air temperature. And

For this reason, the spring force in the valve closing direction of the spring for urging the valve body in the valve closing direction decreases the valve closing force as the outside air temperature rises, so that the outside air temperature proportional to the compressor discharge pressure is reduced. The capacity control related to the outside air load represented by the above-mentioned method does not require a special rod or pressure passage, etc. It is performed without increasing the number of steps. Further, as the compressor housing built-in type, there is also obtained an effect that the degree of freedom of the arrangement position in the compressor housing is excellent without complicating the passage structure.

According to the control valve for a variable displacement compressor according to the second aspect of the present invention, the main spring comprises a normal spring material and biases the valve body in the valve closing direction.
Consisting of a temperature-sensitive material having a positive characteristic with respect to temperature,
It is constituted by a combination of a correction spring in which a spring force acts in a direction to cancel the spring force of the main spring with a force smaller than the spring force of the main spring, and the spring force of the main spring and the spring force of the correction spring Is applied to the valve body.

For this reason, the combined spring force of the spring force in the valve closing direction of the main spring and the spring force of the correction spring acting in the direction to cancel the spring force of the main spring (spring force of the main spring> spring of the correction spring) Force) acts on the valve element, and the correction spring can be made of a general temperature-sensitive material having a positive characteristic with respect to temperature.

According to the control valve for a variable displacement compressor according to the third aspect of the present invention, the correction spring is made of a shape memory alloy.

Therefore, the correction spring can be made of a general shape memory alloy (SMA) having a positive characteristic with respect to temperature.

According to the control valve for a variable displacement compressor according to the fourth aspect of the present invention, the valve housing is inserted and fixed in a control valve receiving hole formed in the housing of the compressor. The pressure response device is fixed to one end of the compressor, and the pressure response device is configured to be attached to a housing of the compressor such that the pressure response device is exposed to the outside through the control valve receiving hole, and the spring is incorporated in the pressure response device. It has been assumed that.

For this reason, the spring incorporated in the pressure responsive device responds to the outside air temperature, and the capacity control that correlates the outside air temperature with the outside air load is performed accurately.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a variable displacement compressor incorporating a control valve according to the present invention.

FIG. 2 is a sectional view showing one embodiment of a control valve for a variable displacement compressor according to the present invention.

FIG. 3 is a graph showing an outside air temperature-spring load characteristic of a correction spring using a temperature-sensitive material used in a control valve for a variable displacement compressor according to the present invention.

FIG. 4 is a graph showing discharge pressure-suction pressure characteristics of a control valve for a variable displacement compressor according to the present invention.

FIG. 5 is a sectional view showing another embodiment of the control valve for a variable displacement compressor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Swash plate type variable displacement compressor 2 Compressor housing 3 Crank chamber 4 Cylinder chamber 5 Piston 7 Drive shaft 9 Wobble plate 14 Suction port 15 Discharge port 23 Control valve receiving hole 24 Crank chamber pressure passage 25 Suction pressure passage 30 Control valve 31 Valve housing 32 Crank chamber side passage 33 Suction port side passage 34 Communication passage 35 Valve chamber 38 Ball valve body 39 Valve seat 40 Valve stem 43 Diaphragm device 45 Diaphragm 49 Diaphragm chamber 50 Sealed chamber 54 Main spring 55 Correction spring 58 Bellows

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ichiro Ogawara 535 Sasai, Sayama City, Saitama Prefecture Sagimiya Manufacturing Co., Ltd. Sayama Plant (72) Inventor Masaki Ota 2-1-1 Toyota-cho, Kariya City, Aichi Prefecture Inside the loom mill (72) Inventor Ken Takeshi 2-1-1, Toyota-machi, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Kenta Nishimura 2-1-1, Toyota-cho, Kariya-shi, Aichi Prefecture Toyota Corporation Inside the Automatic Loom Works (72) Inventor Taku Yasaya 2-1-1 Toyota-machi, Kariya City, Aichi Prefecture F-term in the Toyota Industries Corporation (Reference) 3H045 AA04 AA10 AA12 AA27 AA33 BA12 BA37 CA02 CA24 DA12 DA49 EA13 3H076 AA07 BB32 BB41 CC12 CC16 CC83 CC94

Claims (4)

[Claims] A valve housing having a communication passage communicating the suction port of the compressor with the crank chamber; a valve element for opening and closing the communication path; a spring for urging the valve element in a valve closing direction;
A control valve for a variable displacement type compressor having a pressure responsive device that is driven by the suction pressure of the compressor to drive the valve body in a valve opening direction, wherein the spring is made of a temperature-sensitive material, A control valve for a variable displacement compressor, comprising a responsive spring and reducing a spring force in a valve closing direction with an increase in outside air temperature. And a main spring for urging the valve body in a valve closing direction, and a temperature sensitive material having a positive characteristic with respect to temperature. It is constituted by a combination of a correction spring in which a spring force acts in a direction to cancel the spring force of the spring with a force smaller than the spring force of the main spring, and a combination of the spring force of the main spring and the spring force of the correction spring. The control valve for a variable displacement compressor according to claim 1, wherein a spring force acts on the valve body. 3. The control valve according to claim 2, wherein the correction spring is made of a shape memory alloy. 4. The valve housing is inserted and fixed in a control valve receiving hole formed in a housing of the compressor, and the pressure responsive device is fixed to one end of the valve housing.
2. The pressure responsive device according to claim 1, wherein the pressure responsive device is configured to be attached to a housing of the compressor so as to be exposed outside from the control valve receiving hole, and the spring is incorporated in the pressure responsive device. 4. The control valve for a variable displacement compressor according to 2, 3 or 4.